Clamping device for a tool



Oct. 3, 1967 A. VASS 3,345,114

CLAMPING DEVICE FOR A TOOL Filed July 14, 1965 INVENTOR. ANTAL VASS Flea By Mafia 054% ATTORNEYS United States Patent CLAMPING DEVICE FOR A TOOL Antal Vass, Brom'ma, Sweden, assignor to Areuco Aktiebolag, Stockholm-Vallingby, Sweden Filed July 14, 1965, Ser. No. 471,947 Claims priority, application Sweden,'Sept. 25, 1964, 11,505/ 64 3 Claims. (Cl. 306-20) ABSTRACT OF THE DISCLOSURE A clamping device for removably mounting a tool member upon a support member, comprising at least two guide pins on one member and holes corresponding to the pins in the other member, a shoulder centrally situated in the device and disposed on one member and at least one spring strap fastened to the other member and arranged to snap on to said shoulder, whereby the tool is resiliently attached to the support.

The present invention relates to a clamping device for tools such as press plungers, jaws and the like in working machines. In particular the device is intended to clamp a tool being mounted on a clamp plate or a similar support.

The frequently practised way of fastening a tool in different machines by means of a screw and nut or a locking pin may at times appear to be very complicated and time-consuming. A simplification of the fastening, resulting in a shorter trimming moment upon the exchange of tools when changing to another process, would be desirable.

According to the present invention there is provided a clamping device for removably mounting a tool member upon a support member, comprising at least two guide pins on one member and holes corresponding to the pins, situated on the other member, said pin-s and holes being located on both sides of at least one spring strap, which strap is centrally situated in the device and fastened with one of its ends to one of the members, the other end being bent in order to snap over or under a shoulder a collar or like means disposed on the other member, whereby the tool is fixed to the support by means of spring action.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIGURE 1 shows a clamping device according to the invention in a vertical projection,

FIGURE 2 shows the device in a horizontal projection when the tool is removed, and

FIGURE 3 shows the device in a side elevation.

According to FIGURE 1 the embodiment of the invention shown in the drawing is provided with spring straps 1, 2 which hold a tool 3. As a support for the fastening of the tool a plate 4 is used which is secured to a bar 5 by means of a locking pin 6. The purpose of the bar is to carry the tool and the fastening device and to transmit movements from a source of power, not shown, to the tool.

In the bar end facing the tool there are two curved cuttings 7, 8 positioned on either side of the axis of the bar. The same end of the bar is divided so that a space between two branches 9, 10 is formed and in this space a part of the plate 4 is countersunk. An axial plane of the bar intersecting the branches is at right angles to the axial plane which intersects the two cuttings 7, 8. The plate is provided with two bearing surfaces 11, 12 to which the tool is fixed. From the bearing surfaces guide pins 13, 14 protrude which fit into corresponding holes 15, 16 in the 3,345,114 Patented Oct. 3, 1967 tool. The holes have somewhat greater diameters than the guide pins, so a certain amount of play exists in the fitting between the hole and the pin. The purpose of this clearance is to give the tool flexibility relatively the plate, i.e., the tool can slide on the bearing surfaces in direction so far that the edges of the hole knock against the guide pm.

The device also includes, besides the springs 1, 2, shoulders 17, 18 secured to the tool. In the embodiment shown in the drawing the shoulders are formed by expansions of a socket 19 attached on the surface of the tool facing the plate by means of a screw 20. The socket protrudes into a cavity 21 in the plate and is there surrounded by the free ends of the spring straps 1, 2. The other ends of the spring straps, made of steel wire, are journalled in holes 22, 23 in the plate and rest at the inner parts of the curved cuttings 7, 8 and owing to that a force directed from the centre of the plate and applied at the free end of one of the springs meets a spring action directed to the centre of the plate. When a shoulder is forced into the cavity of the plate the free end of the strap passes aside because the shoulder then pushes the spring away. When the shoulder reaches such a depth in the cavity that its upper edge, facing the tool, comes into the same level as the free end of the strap, the strap snaps over the shoulder. If the shoulder does not reach sufficiently deep to get its upper edge down to the spring end, it is still possible to lift the spring by means of a pair of tongs or the like to above the shoulder and to snap it over. In devices with several springs these are treated in the same Way. The spring straps will then hold the tool fixed to the plate. The tensional force can, to a certain degree, be adjusted by means of the screw 20, which holds the socket 19 and the shoulders in an adjustable distance from the surface of the tool facing the plate. The less the distance between the shoulders and this surface is the more the spring ends have to be lifted to be able to snap over and the greater the force then becomes. To prevent the spring ends from slipping 01f the shoulders, grooves 24, 25 are provided in their upper surfaces the spring ends fitting into the grooves.

When the tool is to be removed from the plate the spring ends are pulled aside by means of a pair of tongs or the like, so that the shoulders come loose and can be pulled out of the cavity, and then the tool is detached from the plate.

The embodiment of the invention shown in the drawing and described above can, of course, be varied. For example, any number of spring straps can be provided and the spring straps can be positioned in the tool and the shoulders on the plate or the guide pins can be provided on the tool with the holes being made in the support member.

What is claimed is:

1. A clamping device for removably mounting a tool member upon a support member, comprising locating means including at least two guide pins on one member and holes corresponding to the pins, situated on the other member said tool member including a body, a socket in said body, said locating means being located on diametric opposite sides of said socket, shoulder means secured to one of said members at least one spring strap, which strap is centrally situated in the device and fastened with one of its ends to one of the members, the other end being bent in order to resiliently engage said shoulder means, whereby the tool is fixed to the support by means of spring action.

2. A device as claimed in claim 1, characterized in that the shoulder means is fastened to the one member by an adjustable screw whereby the distance between the shoulder and the strap may be adjusted.

3 4 3. A device as claimed in claim 1, characterized in that FOREIGN PATENTS the guide pins engage with the holes with a clearance al- 463 006 7/1928 Germany. lowing a limited relative motion between the tool member d th rt an e suppo member 5 EDWARD C. ALLEN, Primary Examiner.

References cted CARL W. TOMLIN, Examiner.

UNITED STATES PATENTS 905,142 12/1908 B W-L.SHEDD,AssistantExammer. 

1. A CLAMPING DEVICE FOR REMOVABLY MOUNTING A TOOL MEMBER UPON A SUPPORT MEMBER, COMPRISING LOCATING MEANS INCLUDING AT LEAST TWO GUIDE PINS ON ONE MEMBER AND HOLES CORRESPONDING TO THE PINS, SITUATED ON THE OTHER MEMBER SAID TOOL MEMBER INCLUDING A BODY, A SOCKET IN SAID BODY, SAID LOCATING MEANS BEING LOCATED ON DIAMETRIC OPPOSITE SIDES OF SAID SOCKET, SHOULDER MEANS SECURED TO ONE OF SAID MEMBERS AT LEAST ONE SPRING STRAP, WHICH STRAP IS CENTRALLY SITUATED IN THE DEVICE AND FASTENED WITH ONE OF ITS ENDS TO ONE OF THE MEMBERS, THE OTHER END BEING BENT IN ORDER TO RESILIENTLY ENGAGE SAID SHOULDER MEANS, WHEREBY THE TOOL IS FIXED TO THE SUPPORT BY MEANS OF SPRING ACTION. 